By Eve Donegan, Sales & Marketing Assistant
David Ehrenfeld is a professor of biology at Rutgers University and holds degrees in history, medicine, and zoology. He is the founding editor of the journal Conservation Biology, lectures internationally, and is the author of The Arrogance of Humanism and Beginning Again. His most recent book, Becoming Good Ancestors,focuses on the interactions, both negative and positive, among nature, community, and our exploding technology, and explains the critical role of honesty in moving towards a sustainable society. In the post below, Ehrenfeld celebrates Earth Day by reviewing the role of environmental restoration in the Florida Everglades.
Environmental restoration is a case in point. We cause environmental damage with comparative ease. We have many ways of doing it: the reckless application of pesticides, indiscriminate use of chain saws and bulldozers, strip mining, carpet bombing, the excessive withdrawal of groundwater, the obliteration of wetlands, the spread of invasive species, and even the relatively rapid alteration of global climate. The speed of the destruction may lead us to think that environmental restoration can be achieved almost as quickly; and the word “restoration” implies a return to the original condition. Yet even though many restorations work well, our most optimistic hopes are not always met.
The environment doesn’t function like the diagrams in the economics textbooks, where the arrows point in both directions, and flows of capital and labor are readily reversible. When the environment is altered, some changes (like species extinctions and introductions) are irreversible, and some (like the removal of topsoil) have a painfully long recovery time.
Take the case of the Florida Everglades. A complex and beautiful ecosystem, a “river of grass” dotted with teardrop-shaped islands of trees, it was created and sustained by the sheetlike flow of water from Lake Okeechobee and the lands to the north. In the last fifty or more years, the Everglades have been dramatically altered by human activity.
The flow of water has been curtailed by agricultural use and diversionary canals, and the trickle that comes into the glades is contaminated with phosphates and mercury. The pattern of wildfires has changed. Ecosystem alteration has imperiled species such as the snail kite and the Cape Sable seaside sparrow. New species, often from released pets, have flourished. The Burmese python, as large as eighteen feet long and 160 pounds, has become common – it can swallow a deer, a pig, an alligator, or presumably a person. The introduced climbing fern, Lygodium, coats and smothers native vegetation. Intense development along the Miami corridor to the east consumes groundwater, which leads to saltwater intrusion in the aquifers, and the traffic and other human impacts all have their effect.
What can be done to restore the Everglades? Part of the answer is that if a dependable flow of relatively clean water is once again made available, damage can be slowed or halted in the central part of the remaining Everglades, and natural recovery will be given a chance. The State of Florida has already spent a vast amount of money to achieve this, with preliminary success, and the federal government has promised to spend more. But it would be foolish to expect that the existing phosphate and mercury will have no lingering effects, the exotic animals and plants will all be controlled, that human population on the park’s eastern border will cause no further changes, or even that the rapidly rising sea level can somehow be completely contained.
It is harder to achieve environmental restoration in some places than in others. In the remaining intact areas of the peatlands of Canada and northern Europe and the rainforests of the Amazon, the Congo, and Australia, preservation is still an option but extensive restoration is not likely in the foreseeable future. On the other hand, restoration is thriving in urban areas, with the replacement of brownfields and concrete deserts by parks and gardens. Wetland and prairie restoration is an exciting new science with many success stories. Some endangered species – the peregrine falcon, the wolf, and the Costa Rican nesting population of green sea turtles – have responded dramatically to restoration efforts. The mixed deciduous forests of New England recover most of their species and much of their beauty a mere 50-75 years after cutting, with minimal management on our part. Even in New England, however, new diseases and pests introduced by human activity – gypsy moths, sudden oak decline, beech bark disease, emerald ash borers, hemlock wooly adelgids – may make restoration to the “original” forest impossible.
Environmental restoration is vitally necessary, and it deserves a far greater commitment of resources and effort than it is getting. But we have to guard against unrealistic assumptions about what it is possible for a restoration to do. In any particular restoration, everyone should decide at the outset what an acceptable end result will be – not necessarily a carbon copy of what was once there. Restoring processes, such as proper water flow in the Everglades, is likely to be easier and faster to achieve than restoration of the original species composition and ecosystem structure. Given enough time, an acceptable plant and animal community will follow the repair of ecosystem processes, but there is a good chance that it will not be exactly like the original one. Appreciate it for what it is.